Network bus coupler and system

ABSTRACT

A system for coupling an avionics component to a bus includes a junction box electrically coupled to the avionics component and to the bus. A circuit card disposed in the junction box includes a plurality of sockets. The some of the sockets are electrically connected to the bus. Others of the sockets are electrically connected to the avionics component. A modular network bus coupler is mountable to the circuit card. The bus coupler includes a housing with electrical isolation circuitry disposed therein. A plurality of pins are disposed exterior of the housing and engageable with at least some of the sockets of the circuit card. At least some of the pins are electrically coupled to the electrical isolation circuitry.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of Provisional ApplicationNo. 60/400,423, filed Aug. 1, 2002, and titled NETWORK BUSCOUPLER-IN-A-CAN.

FIELD OF THE INVENTION

The present invention relates generally to the field of electricalconnectors, and more particularly to a modular network bus connector forelectrically coupling devices such as avionics components to a data busin an aircraft.

DESCRIPTION OF THE PRIOR ART

In an aircraft data management system according to Mil. Std. 1553,various avionics components, such as communications, navigation, GPSequipment and the like, communicate through a network bus. The typicalMil. Std. 1553 bus design incorporates a redundant loop of twisted,shielded wires, to which all avionics components are connected. Digitaldata may be shared from one avionic component to others using the loopas a path.

Avionics components are typically connected to the bus using a stub,which is a pair of wires. If the stub is spliced directly to the bus, ashort in the stub will destroy the integrity of the entire network. Toavoid the shorting problem, an isolation transformer may be incorporatedinto the stub circuit to isolate the stub from the network if a shortoccurs. Couplings that integrate isolation transformers and a networkstub connection are well known to those skilled in the art. Thesecouplings are spliced into the network bus.

Couplings that are connected to the network using crimped or solderedsplices have several problems. For example, splices may be unreliable inan aviation environment because the constant, and frequently severe,vibration during flight tends to fatigue the splices to the point offailure.

The stubs that extend from spliced couplings are also exposed topotential damage from other environmental conditions. When a faultoccurs in the network, technicians must connect a bus analyzer to atwisted, shielded pair of wires. The bus analyzer will typicallyindicate that one of the wires is shorted to the shield or to ground.The technicians will then wring or twist the wires in an effort todiscover the location of the short. This wringing actually causesgreater damage to the bus wires.

Spliced couplings are typically bulky and require an elaborate wiringharness to connect avionics to the bus. As a result, the splicedcouplings require a relatively large volume of space in the aircraft. Alarge volume is undesirable because aircraft space and weightrequirements are limited in order to maintain the desired power toweight ratio and optimize aircraft performance. Moreover, designers mustexpend time and effort locating mounting points for the couplers and theassociated wires. The complexity of the aircraft is consequentlyincreased, which increases production and maintenance costs.

SUMMARY OF THE INVENTION

The present invention provides a system for coupling a device to a bus.The system includes a junction box electrically coupled to the deviceand to the bus. A circuit card disposed in the junction box includes aplurality of sockets. Some of the sockets are electrically connected tothe bus. Others of the sockets are electrically connected to the device.A modular network bus coupler is mountable to the circuit card. The buscoupler includes a housing with electrical isolation circuitry disposedtherein. A plurality of pins are disposed exterior of the housing andengageable with at least some of the sockets of the circuit card. Atleast some of the pins are electrically coupled to the electricalisolation circuitry.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an aircraft integrated wiring system.

FIG. 2 is a plan view of a network coupler according to the presentinvention mounted to a circuit card of a wiring integration assembly.

FIG. 3 is a side view of a network coupler according to the presentinvention.

FIG. 4 is a bottom view of a network coupler according to the presentinvention.

FIG. 5 is a schematic diagram of a two stub embodiment of a networkcoupler according to the present invention.

FIG. 6 is a schematic diagram of a four stub embodiment of a networkcoupler according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings, and first to FIG. 1, part of an aircraftintegrated wiring system is designated generally by the numeral 11.Integrated wiring system 11 includes a bus controller 13 that isconnected to a plurality of wiring integration assemblies 15 by a bus17. In the preferred embodiment, bus 17 is implemented as part of a flatmulti-wire assembly. Wiring integration assemblies 15 comprise junctionboxes.

Avionics devices 19 are connected to wiring integration assemblies 15 bystubs 21. Avionics devices 19 may comprise navigational devices such asglobal positioning system devices, flight control system devices,communications devices, weapons system devices, and the like. Avionicsdevices 19 may share and exchange digital information through bus 17.

Referring now to FIG. 2, circuit cards such as circuit card 23 arepositioned within wiring integration assemblies 15. Circuit card 23includes an array of sockets 25. Wires of bus 17 and stubs 21 areconnected to appropriate sockets 25. A modular network bus coupler 27 ismounted to circuit card 23.

Referring now to FIGS. 3 and 4, bus coupler 27 includes a housing 29.Housing 29 may be made of a suitable material such as cold rolled steel.A plurality of pins 31 extend outwardly from the bottom of case 29. Pins31 are sized and configured to be inserted into socket 25 of circuitcard 23, thereby establishing an electrical connection with a socket 25.A gasket 33 of a suitable material, such as silicone rubber, may bepositioned on the bottom of case 29 around pins 31. As will be explainedwith respect to FIGS. 5 and 6, case 29 contains electrical componentsthat are connected to various pins 31.

Referring now to FIG. 5, there is illustrated the electrical circuitryof a two stub embodiment of the present invention. Pins B1 and D1 areadapted for connection to the high side loop of bus 17. Pins B3 and D3are adapted for connection to the low side loop of bus 17. Pin B2 isadapted to be connected to ground. Pins D2 and C2 are adapted to beconnected to the bus to provide bus termination. A termination resistor41 positioned within case 29 is connected between pins D2 and C2.

Bus pins B1, B3, D1 and D3 are connected to isolation transformers 43and 45 through isolation resistors 47-53. Isolation transformer 43 isconnected to pins A1 and A2. Pins A1 and A2 are adapted for connectionto the high side of a stub and the low side of the stub, respectively,connected to a device 19. Isolation transformer 45 is electricallyconnected to pins X1 and A3, which are adapted for connection to thehigh side of a stub and the low side of the stub, respectively, of adevice.

Referring now to FIG. 6, there is illustrated a four stub embodiment ofthe bus coupler of the present invention. Pins B1 and C1 are adapted forconnection to the low side loop of bus 17. Pins B3 and C3 are adaptedfor connection to the high side loop of bus 17. Pins B1, C1, B3 and C3are electrically connected to isolation transformers 61-67 throughisolation resistors 71-85.

Isolation transformer 61 is connected to pins A2 and A3, which areadapted for connection to the low side of a stub and the high side ofthe stub, respectively. Similarly, pins A1 and X1 are adapted forconnection to the low side of a stub and the high side of the stub,respectively. Pins D2 and D3 are adapted for connection to the low sideof a stub and the high side of a stub, respectively, finally, pins D1and X2 are adapted for connection to the low side of a stub and the highside of the stub, respectively.

From the foregoing, it may be seen that the bus coupler of the presentinvention overcomes many of the shortcomings of the prior art. Thesystem of the present invention eliminates the cost and weightassociated with bulky wiring harnesses. The wiring design is alsosimplified and the components are in easily located and accessibleintegrated wiring assembly junction boxes. The system of the presentinvention significantly reduces the time and expense associated withtrouble shooting and maintenance. If a fault occurs in the wiringsystem, maintenance personnel may simply unplug a suspected defectivebus coupler 27 and replace it with a new bus couple 27. This simplereplacement procedure greatly simplifies fault repair.

While the present invention has been described with reference topreferred embodiments, this description is not intended to be construedin a limiting sense. Various modifications and combinations of elements,as well as other embodiments of the invention, will be apparent to thoseskilled in the art given the benefit of this description.

1. A network bus coupler, which comprises: a housing; electricalisolation circuitry disposed within the housing; and, connectorsdisposed exterior of the housing and electrically coupled to theelectrical isolation circuitry.
 2. The network bus coupler as claimed inclaim 1, wherein said connectors comprise a plurality of pins.
 3. Thenetwork bus coupler as claimed in claim 2, wherein said pins are adaptedfor insertion into sockets.
 4. The network bus coupler as claimed inclaim 3, wherein said sockets are contained in a circuit card of ajunction box.
 5. The network bus coupler as claimed in claim 1, whereinsaid isolation circuitry includes an isolation transformer.
 6. Thenetwork bus coupler as claimed in claim 1, including: a bus terminatordisposed in said housing and electrically coupled to a connectordisposed exterior of said housing.
 7. A system for coupling an a deviceto a bus, said system comprising: a junction box electrically coupled tosaid device and to said bus; a circuit card disposed in said junctionbox, said circuit card including a plurality of sockets; and, a modularnetwork bus coupler mountable to said circuit card, said bus couplercomprising: a housing; electrical isolation circuitry disposed withinthe housing; and, a plurality of pins disposed exterior of the housingand engageable with at least some of said sockets of said circuit card,at least some of said pins being electrically coupled to said electricalisolation circuitry.
 8. The system as claimed in claim 7, wherein saidisolation circuitry includes an isolation transformer.
 9. The system asclaimed in claim 7, including: a bus terminator disposed in said housingand electrically coupled to a pair of said pins.
 10. The system asclaimed in claim 7, wherein said device is an avionics component andsaid bus is an aircraft data bus.